Vortex tube

[1] It has no moving parts and is considered an environmentally friendly technology because it can work solely on compressed air and does not use Freon.

A conical nozzle allows gas specifically from this outer layer to escape at that end through a valve.

The gas in the central vortex is likewise cooler upon its return to the starting-point, where it is released from the tube.

This equation was published in 2012; it explains the fundamental operating principle of vortex tubes (Here's a video with animated demonstration of how this works[5]).

Compressed gas at room temperature is expanded in order to gain speed through a nozzle; it then climbs the centrifugal barrier of rotation during which energy is also lost.

It is specifically tailored to the geometrical shape of the vortex tube and the details of its flow and is designed to match the particular observables of the complex vortex tube flow, namely turbulence, acoustic phenomena, pressure fields, air velocities and many others.

However, due to the complexity of the vortex flow this empirical approach was able to show only aspects of the effect but was unable to explain its operating principle.

[10] German physicist Rudolf Hilsch [de] improved the design and published a widely read paper in 1947 on the device, which he called a Wirbelrohr (literally, whirl pipe).

In 1951 Curley and McGree,[13] in 1956 Kalvinskas,[14] in 1964 Dobratz,[15] in 1972 Nash,[16] and in 1979 Hellyar [17] made important contribution to the RHVT literature by their extensive reviews on the vortex tube and its applications.

[20] [21] Vortex tubes also seem to work with liquids to some extent, as demonstrated by Hsueh and Swenson in a laboratory experiment where free body rotation occurs from the core and a thick boundary layer at the wall.

It was found that when the inlet pressure is high, for instance 20-50 bar, the heat energy separation process exists in incompressible (liquids) vortex flow as well.

Commercial vortex tubes are designed for industrial applications to produce a temperature drop of up to 71 °C (160 °F).

A control valve in the hot air exhaust adjusts temperatures, flows and refrigeration over a wide range.

This eliminates or drastically reduces the need for liquid coolant, which is messy, expensive, and environmentally hazardous.